56.
Your Answer is
Correct Answer is H
Explanation
Item H: it refers to the book The Sun Also Rises in the previous sentence, correct.
Item F: The main-slave conjunction while appears at the beginning of the sentence, and two sets of subject-predicates are required later, so the underlined part should be a subject-verb structure.
G item: Their is a possessive and needs to be followed by a noun.
J item: things refer to unknown.